Tension device for sewing-machines.



A. D. SMITH.

TENSION DEVICE FOR SEWING MACHINES.

APPLICATION FILED DEC. 7, 1909. 1,1 28,377. Patented Feb. 16, 1915.

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A. D. SMITH. TENSION DEVICE FOR SEWING MACHINES.

APPLICATION IILBD DEC. 7, 1909.

1,128,377. Patented Feb. 16, 191 5.

2 SHEETS-SHEET 2.

barren STATES PATENT orrron.

ALBERT D. SMITH, OF BELVIDERE, ILLINOIS, .ASSIGNOR TO NATIONAL SEWING MACHINE COMPANY, OF BELVIDERE, ILLINOIS, A CORPORATION OF ILLINOIS.

TENSION DEVICE FOR SEWING-MACHINES.

Specification of Letters Patent.

Patented Feb. 16, 1915.

Application filed December 7, 1909. Serial No. 531,847.

This invention relates to improvements in thread checks and tension devices for sewing machines, and one of the objects of the invention is to provide an improved, simple and efficient thread check of this character which will automatically accommodate itself to threads of varying sizes without necessitating manual adjustment of the check and without subjecting the thread of any size to excessive strain.

A further object is to provide an improved device of this character comprising a pair of opposed elastic members or springs of different tension and between which the threads are adapted to pass, one of the elastic members being adapted to yield and to exert its tension upon the threads to a certain size and the other elastic member being adapted to yield and to exert its tension upon the coarser or larger threads and without subjecting the weaker elastic memher to undue strain.

- A further object is to provide improved means for guiding and directing the threads between the elastic members, and improved means for retaining the thread in position.

A further object is to provide a tension pulley over which the thread passes. and improved means for preventing the thread from being wrapped around the shank of the pulley.

A. further object is to provide improved means whereby the tension of the pulley may be adjusted to accommodate special work, and which means is located not only out of the way of the ravelings and the goods, but at a place where it cannot be interfered with by an inexperienced operator.

To the attainment of these ends and the accomplishment of other new and useful objects as will appear, the invention consists in the features of novelty in the construction, combination and arrangement of the several parts hereinafter more fully described and claimed and shown in the accompanying drawings illustrating the embodiment of the invention, and in which- Figure l is a front elevation of a portion of the face plate on the head or arm ofa machine having an attachment applied constructed in accordance with the principles of this invention. Fig. 2 is an elevation taken from the right hand side of Fig. L Fig. 3 is a view taken on line 33 of Fig. 2 and on line 3'3 of Fig. 5. Fig. 4 is a view taken on line 4.4 of Fig. 3. Fig. 5 is a view taken on line 55 of Fig. 3 and showing a thread of ordinary size in position between'the elastic members. Fig. 6 is a view similar to Fig. 5, showing a coarser thread between the elastic members. Fig. 7 is a detail perspective view of the support for the elastic members and also for the tension pulley. Fig. 8 is a sectional view on line 8-8 of Fig. 9. Fig. 9 is a sectional View on line 99 of Fig. 8. Fig. 10 is a sectional View on line 1010 of Fig. 9. Fig. 11 is a detail perspective view of the cam for automatically releasing the tension of the pulley. Fig. 12 is an elevation of the tension pulley. Fig. 13 is a sectional view on line 13-18 of Fig. 10.

Referring more particularly to the drawings and in the present exemplification of the invention the numeral 15 designates the face plate which is removably secured to the front of the head or arm 16 of the sewing machine in the ordinary and usual manner, and is provided with the slot 17 through which the usual take-up arm 18 projects. 19 designates the upper extremity of the needle bar, and 20 the adjusting screw for varying the tension of the presser-foot. All of these parts are of the usual and ordinary construction and form no part of the present invention.

Secured in any desired position and to any suitable support, but preferably a face plate 15, is a support designated generally by the reference numeral 21, and this support is provided with an enlarged portion 22, which preferably projects laterally beyond one side of the support 21, and is providedwith a flat face 23. Adjacent the free extremity 24: of this laterally projecting portion 22 is anupright groove 25, and the edges of the portion 22 are preferably cut away or beveled as at 26 adj aceni; the groove 25 to permit the thread 28 to enter the groove 25 and to prevent the formation of sharp or abrupt corners over which the thread would pass. This upright groove 25 maybe of any desired width and is preferably of a depth to accommodate thread varying from what is known as size to size 200. The portion 22 is also provided witha slot or groove 29, which intersects the groove '25 and preferably extends through the extremity 24 of the portion 22, as shown more clearly in Figs. 2, 5 and 6.

An elastic member 30 in the form of a spring is secured by one extremity 31, as shown more clearly in Figs. 5 and '6, on the portion 22 of the support 21, so that the body portion of the elastic member projects into the slot 29. The free extremity 32 of thiselastic member is curved or rounded as recess shown to permit the thread to readily pass over the extremity. The normal tendency of the elastic member 30 is to hold the body portion projected out of the groove or slot 29 and the extremity 32 stands adjacent a recess 33 in the portion 22 of the support 21, so that when the body portion of the elastic member 30 is forced into the groove or slot 29 the extremity 31 will be forced into the The groove 29 is of a depth to receive the body portion of the elastic member and when the elastic member is forced into the groove 29 in the manner to be set forth, the portion thereof which extends across the groove 25 will rest against the bottom of the groove 29 to protect the elastic member 30 from being strained. A second elastic member 34 preferably in the form of aleaf spring is secured to the portion 23 of the support 21 in any desired or suitable manner, preferably by means of fastening de vices 35, such as screws or bolts which pass through the elastic member 34 adjacent one extremity and into threaded apertures 36 in the portion 22 of the support 21 adjacent the extremity 31 of the elastic member 30. This elastic member 34 is preferably ofa width somewhat greater than the elastic member 30 and is such a length that the extremity 37 thereof will stand adjacent the free extremity 24 of the portion 22, and this extremity 37 of the elastic member 34 is preferably curved or deflected, as shown, and away from the elastic member 30, and coiiperates with the extremity 32 of the elastic member 30 for directing the thread between the elastic members. If desired, the extremity 24 of the portion 22 of the support may be beveled as at 38, and serves as an additional means for guiding the thread into position.

The elastic member 34 is constructed of stiffermaterial than the elastic member 30, that is of a material so that the elastic memelastic member 30. The object of constructing these elastic members 30 and 34 of different tension is for the purpose of accommodating threads of various sizes, that is when a thread of the ordinary thickness,

say from size 20 to size 200, is inserted between the elastic members as shown in 5, the elastic member 30 Wlll yleld to accommodate these sizes and cooperates with ency of the thread is to force the elastic member 30 into the groove 29 until the clastic member is preventedfrom further adjustment by the thread by coming in con- ,1

tact with the bottom of the groove. if the thickness of the thread is greater than the depth of the slot or groove 25 when the thread is placedtherein, it will be apparent that the elastic member 34 will be adjusted bythe thread, that is the elastic member will be brought into action to exert its tension on the thread. When the thread is withdrawn and a smaller thread inserted,

the elastic member 30 will assume its nor- 2,

21 may be removably held in position in it.

any desired or suitable manner, preferably by means of a fastening screw 39, which passes through a suitable aperture 40 in the support 21 and into the face plate 15.

The lower extremity of the support 21 is provided with a recess designated generally by the reference numeral 41, and which recess opens through the front face of the support, and an aperture 42 is arranged at the center of the recess and passes through the bottom thereof. A tension pulley 43 is provided with a groove 44 in its periphery and an aperture 45 passes therethrough. The faces of the pulley are concaved as at 46, 47, shown more clearly in Fig. 9, and the bottom of the recess 41 is preferably convexed as at 48. This recess 41 is adapted to receive one face of the pulley so that the edge 49 thereof will be set into the face of the support, that is the edge 49 will be located within the plane of the faces of the support to prevent the thread from passing around the shank of the pulley instead of in the groove 44 thereof when the machine is being threaded. An axle 50 is provided with a head 51, which. head is of a diameter somewhat larger than the aperture 45 in the pulley so that when the shank-50 passes through the aperture 45 the head 51 will have an extended frictional contact with the concaved face 47 of the "When this larger size 0 pulley. The shank thus formed by the axle 50 passes through the aperture 42 in the support 21 and through an aperture 52 in face plate 15, so as to project into the head 16 of the machine, and the extremity of the shank is provided with grooves 53 on opposite sides thereof and into which grooves the arms 54 forming a bifurcated extremity of. an elastic member or leaf spring 55, project. This elastic member 55 is arched longitudinally as shown, with the convexed side restmg against the inner face of the face plate 15, and is supported and secured in position by means of an adjusting screw 56, which passes through the extremity 57 and engages the face plate 15. WVhen thus secured in position, the elasticity of the member 55 will draw the shank or axle 5O inwardly and the head 51' thereof against the face 47 of the pulley and will in turn force the pulley inwardly so that the concaved face 46 will have frictional contact with the convex bottom 48 of the recess 41. If desired, a packing 58 may be disposed between the bottom of the recess 41 and the tension pulley 43. With this improvediconstruction, the tension of the elastic member 55 may be varied or adjusted by adjusting the fastening screw, and this adjustment is made at the factory and so regulated that the tension pulley will accommodate threads between certain sizes. It will also be seen that when the face plate 15 is secured in position, the adjusting screw will be protected not only from the ravelings of the goods, but will be located in a place where it cannot be interfered with or adjusted by an inexperienced operator, while at the same time an experienced operator may, if desired, adjust the screw 56by removing the plate 15 and thereby'vary the tension of the elastic member so as to adapt the machine to special work.

Any suitable means may be provided for bodily adjusting the tension pulley or releasing the tension thereon when the presserfoot is raised so as to permit the thread to be easily fed when it is desired to remove the work. A suitable and efficient means for accomplishing this purpose comprises a cam 59. which is supported by a member 60, the extremities 61-62 of which are deflected laterally and are provided with apertures 63.64 therein and through which apertures the bar 65 to which the presser-foot' 1s connected, passes. One of the laterally pro ecting portions, preferably the lowermost one 62, is provided with an extension 66, wh ch projects into an elongated slot 67 in the side of the head of the sewing machlne. The usual cam lever 68 is pivoted as at 69 to a portion of the sewing machine head and is arranged so that the projecting portion 66 on the member 60 will engage and rest upon the cam to hold the member 60 in position and also to raise the member when the cam is raised. An elastic member 70, such as a co l spring'or the llke, is secured by one extremity, preferably to the projecting portion 61, andis anchored as at 71, preferably to the presser-bar 65. This elastic member portion 72, against which the cam engages.

A further movement of the cam lever 68 in 70 tends to hold the projecting portion 66 the same direction to force the. member 60 v upwardly, will cause the cam 59 to force the shank or axle 50 forwardly against the tension of the'elastic member 55 to move the head 51 out of engagement with the face 47 of the tension pulley 43, thereby releasing the pulley 43 to permit the pulley to revolve freely when the thread 28 is drawn thereover. When the presser-foot is lowered by moving the cam lever 68 in the opposite direction in the ordinary and well known manner, the elastic member 7 Owill draw the member 60 downwardly and with it the cam 59. As the cam 59 moves away from the shank or axle 50, the tension ,of the elastic member 55 will be exerted upon the shank or axle 50 and will draw the head 51 thereof into engagement with the face 47 of the tension pulley and force the latter into the recess 41 of the support 20, so that the face 46 thereof will have frictional engagement with the convexed face 48 of the bottom of the recess 41;

In threading the machine, the thread 28 is first passed between the elastic members 3O34 and then passed once around the tension pulley 43 and then downwardly toward the needle, as shown more clearly in Figs. 1 and 2, so that when the take-up arm '18 is reoiprocated in the ordinary and well known manner, it will draw the thread over the tension pulley and through the check so as to prevent the thread from being paid off too rapidly from the spool.

The support 21 may be secured to the face plate 15 in any desired or suitable manner,- such as by means of a fastening screw 7 3, which passes through the plate 15 from the inner face thereof and into thesupport 21'.

In order that the invention might be understood the details of the foregoing embodiment thereof have been thus specifically described, but i What is claimed as new is: j

1. In a thread check for sewing machines the combination of a pair of yieldable mem-' bers adapted to grip a thread passing there between, and means effective after ene of said members have yielded a certain amount to reinforce said member and cause the other member toyield when threads greater than a' ce'rtain size are passed between said yielding members.

2. In a device of the character described, two tension members, means for causing said a members to act conjointly to apply yielding tension to threads of certain sizes, and meanslfor causing one of said members to act independently of the other to apply yielding tension to threads of certain other sizes. Y V

3, In a thread tensioning device, two yielding members, means for limiting the tension applied by said device on threads of less than a certain size to the degree of tension exerted by one of said tension memhers, andmeans for exerting greater tension on threads larger than said certain size.

4-. In a tension de ice for sewing machines, two yielding tensionmembers adapted to act simultaneously on threads of certain sizes, and means for preventing one of said members from exerting yielding tension on threads of certain other sizes.

, 5. A thread check for sewing machines comprising opposed elastic members of different tension between which the thread is yieldingly gripped, a co-acting member adapted to resist the flexingof the weaker of said elastic members to cause the stronger elastic member to fiex when the thread is greater thana certain size, and a guide for holding the thread against displacement.

6. In a device of the character described, the combination of a support provided with a groove therein, an elastic member secured to the support and disposed over the groove, a second elastic member secured to the support and cooperating with the first elastic member, both of said members having en- -gagement with the thread and between which elastic members the thread passes, the first said elastic member being adapted to be forced into the groove by the threadwhen the latter is in position between the members.

'7. In a device of the character described, the combination of a support provided with a groove therein, an elastic member secured to the support and disposed over the groove, a second elastic member secured to the support and cooperating with the first elastic member both of said members having engagement with the thread and between which elastic members the thread passes, the first said elastic member being adapted to be forced into the groove by the thread when the latter is in between the members, said elastic members having a different tenslon. V

. 8. In; a device of the character described, the combination of a support provided with a grofove opening through the face thereof, a thread groove also opening through the face of the support and crossing the first said groove, a pair of cooperating elastic members secured to the support and extend.- ing across the thread groove and between which elastic members the thread passes, one of, said elastic members being adapted to be forced into the first said groove when a thread is in position between the elastic members and in the thread groove.

9. In adevice of the character described, the combination of a support provided with a groove opening through the face thereof, a, thread. groove also opening through the face of the support and crossing the first said groove, a pair of cooperating elastic members secured to the support and extending across the thread groove and between which elastic members the thread passes, one of said elastic members being adapted to be forced into the first said groove when a thread is in position between the elastic members and in the thread groove, the other elastic memberextending across the thread groove and adapted to be forced away from the support by a thread of large diameter when the first said elastic member engages the bottom of the first said groove.

l0. In a device of the character described, the combination of a support provided ith a groove opening through the face thereof, a thread groove also opening through the face of the support and crossing the first said groove, a pair of cooperating elastic members of different tension secured to the support and extending across the thread groove and between which elastic members the thread passes, one of said elastic members being adapted to be forced into the first said groove when a thread is in position between the elastic members and in the thread groove.

11. In a device of the character described, the combination of a support provided with a groove opening through the face of the support, there being a thread groove also openingthrough the face of the support and crossing the first said groove, a pair of elasticmembers supported to extend across said ,second thread groove and between which members the thread passes, one of the elastic members standing over the first said groove, the elasticity of said member tending normally to force the member out of the groove and against the other elastic member, to ,grip the thread, the first said elastic member being adapted to be forced away from the other elastic member and into the first said groove when a coarse threadis passed between the members, said other elastic member yielding to the coarse thread, I

12. In a device of the character described,

the combination of a support provided with a groove opening through the face thereof, there being a thread groove also opening through the face of the support and crossing the first said groove, a pair of elastic members supported to extend across said second thread groove and between which members the thread passes, one of the elastic members standing over the first said groove, the elasticity of said member tending normally to force the member out of the groove and against the other elastic member, to grip the thread, the first said elastic member being adapted to be forced away from the other elastic member and into the first said groove when a coarse thread is passed between the members, said other elastic member yielding to the coarse thread, the entrance extremities of the elastic members being deflected away from each other for directing the thread between said members.

13. In mechanism of the class described the combination of a sewing machine head,

a a pair of yielding members of relatively of elasticity between.

of said yielding members being irresponsive to threads of certain sizes, an abutment for reinforcing the weaker members when threads larger than said certain sizes are passed between said members so as to cause the stronger of said members to respond, and a guide for positioning the thread with respect to said yielding members.

14. In a device of the character described, the combination of a thread check comprising opposed elastic portions between which the thread passes, a support provided With a recess having a convex bottom, a pulley having a concave face journaled to the support with said face standing within the recess adjacent the convex bottom and with the peripheral edge of said face disposed below the surface of the'support and within the recess, means for creating a tension on the pulley to retard its rotation, and means for releasing the tension at will.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, on this 3rd day of December, A. D. 1909.

ALBERT D. SMITH.

Witnesses:

E. L. FREENE, FRANK I. Nnrr.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

. Washington, D. 0." 

